(1) Field of the Invention
The invention relates to an adjusting mechanism for the lens set of an imaging system, and more particularly to which is built in a digital imaging system to carry out the view-direction adjustment of the lens set.
(2) Description of the Prior Art
Conventional digital camera such as one disclosed in U.S. Pat. No. 5,612,732 has its lens set movable about a single axis. Thus, a single degree of freedom for the lens set is obtained in the work. As an improvement over the preceding work, another prior art disclosed in ROC Pat. Publication No. 286783 (Application No. 85201588) introduces a lens set which is capable of limited sliding and rotation. However, both of aforesaid prior arts have to use bare hands to turn the lens for any adjusting intend. Moreover, they have the following common disadvantages.
1. The lens may be smeared easily during adjusting, and which will lead to poor photo quality.
2. Adjusting by hand s is usually not precise, but rough and rude. Such movement could not only cause possible damage at the lens structure, but also contribute to unexpected internal movement inside the camera housing. As a consequence, degradation in lens focusing and camera durability might be inevitable.
Because of these drawbacks, digital camera is usually ranged to relatively low precision requirement products, and is not adaptable to high-end products which usually demand high degree of lens cleanness and more precise focusing.
Therefore, an invention devoting to resolving aforesaid disadvantages of conventional adjusting mechanism for the lens set of an imaging system is necessary, definitely.
Accordingly, it is a primary object of the present invention to provide an adjusting mechanism for the lens set of an imaging system, which will make broader its photo-taking range by utilizing universal ball joints.
It is another object of the present invention to provide an adjusting mechanism for the lens set of an imaging system, which makes the lens precisely adjustable by applying separate X- and Y-axis driving units.
It is a further object of the present invention to provide an adjusting mechanism for the lens set of an imaging system, which can avoid direct hand contact on the lens and reduce the possibility of lens damage by employing a human-machine interface.
The adjusting mechanism for the lens set of an imaging system in accordance with the present invention, which is applied to digital photo-taking system, monitoring system, and the like for precisely adjusting the lens set thereon, comprises a pivoting means, a driving means for controlling the lens set, and a human-machine interface for controlling the driving means. By the pivoting means and the driving means, the lens set of the imaging system according to the present invention, then, can obtain a cone-shape accessible region of the lens set, with the cone tip located inside the imaging system.
According to the invention, the pivoting means, which is connected to the anchoring end of the lens set inside the imaging system and provides three rotational degrees of freedom to the anchoring end, can be a ball joint, a universal joint, or any as the like. Preferably, the pivoting means is a ball joint comprising a ball housing fixedly located to the imaging system and a ball-shape terminal, which is connected with the anchoring end of the lens set and is restricted and limited rotationable inside the ball housing. In case that the pivoting means is a universal joint, one of the terminal of the universal joint is connected fixedly to the imaging system, and the other terminal connected with the anchoring end of the lens set.
According to the present invention, the driving means located inside the imaging system is utilized to drive the lens set rotating inside the cone-shape accessible region with the pivoting means as the rotation center. Preferably in the first embodiment according to the present invention, the driving means further comprises a first electromagnetic-controlled element and a second electromagnetic-controlled element.
The first connecting arm of the first electromagnetic-controlled element as the output of the first electromagnetic-controlled element, which is a flexible arm with its protruding length controlled by the first electromagnetic-controlled element, can be a two-section arm with two sections universally jointed in the middle of the arm, with one end connected with the first electromagnetic-controlled element and with the other end ball jointed to the middle of the lens set.
Similar to the structure described in the first electromagnetic-controlled element, the second electromagnetic-controlled element according to the present invention has a two-section second connecting arm. However, the installation of the second electromagnetic-controlled element and the second connecting arm is not parallel to, or along the same line with, the installation of the first electromagnetic-controlled element and the first connecting arm. Such arrangement of the driving means can make the lens set X- and Y-axis adjustable.
In the second embodiment according to the present invention, the driving means comprises a first gear-and-rack set and a second gear-and-rack set. The gear of the first gear-and-rack set is driven by an electrical motor, and the rack engaged with the gear is ball jointed to middle of the lens set by a ball joint located at one end of the rack.
Similar to the structure described in the first gear-and-rack set, the second gear-and-rack set according to the second embodiment has a gear driven by another electrical motor and a rack engaged with the gear and ball jointed to middle of the lens set by a ball joint located at one end of the rack. However, the installation of the second gear-and-rack set not parallel to, or along the same line with, the installation of the first gear-and-rack set. Such arrangement of the driving means can make the lens set X- and Y-axis adjustable.
In the third embodiment according to the present invention, the driving means comprises a carrier and a third gear-and-rack set. The carrier driven by an electrical motor is a rotational platform for bearing the pivoting means and the third gear-and-rack set. The third gear-and-rack set further comprises a gear driven by another motor and a rack engaged with the gear at one side and ball jointed to middle of the lens set at the other end. The arrangement of the third gear-and-rack set can""t be perpendicular to the rotation axis of the carrier so that the lens set can be X- and Y-axis adjustable by the third embodiment of the driving means.
The human-machine interface according to the present invention is a means for facilitating the operator to control the driving means indirectly. Preferably, the human-machine interface is a displacement-sensing means, and further comprises a rotation ball and a sensing unit. The rotation ball is utilized to generated angular displacement by human activation. The sensing unit located around the rotation ball is used for detecting the angular displacement of the rotation ball and for providing a status signal to control the driving means, and further comprises preferably an X-axis sensor, a Y-axis sensor, and a reference sensor for supplying reference status signal. By providing these three sensors, the angular displacement of the rotation ball can be observed accurately and can be used to activate the driving means.
In another embodiment according to the present invention, a hand control means can be used to replace the driving means and the human-machine interface for controlling motion of the lens set. The hand control means can be a four-bar linkage to control the positioning of the lens set directly, and no need of any electrical motor in the adjusting means is necessary.
According to the present invention, the four-bar linkage can be an a planar rectangular linkage installed inside the imaging system, with the input bar accessible to the foreign control activation (hand motion, for example) and the extended output bar connected with the lens set via a sliding track means. The sliding track means comprises a slider ball jointed to the output bar of the four-bar linkage, and a track located on the circumference of the lens set and along the longitudinal direction of the lens set to accept the slider. Preferably, the plane where the four-bar linkage locates is perpendicular to the center line of the cone-shape accessible region of the lens set. By providing the four-bar linkage, the sliding track means at end of the output bar and the pivoting means, the lens set in accordance with the present invention can be easily adjusted anywhere in the cone-shape accessible region.
According to the present invention, aforesaid ball joints can be replaced with universal joints or any as the like; similarly, aforesaid universal joints can be substituted by ball joints or the like.
All these objects are achieved by the adjusting mechanism for the lens set of an imaging system described below.